Active Users numbers reported contradict with other metrics

[Nadhir Boukorsi]

Hi, I have an app that in recent months, active users have increased too much to 130k daily and 3.5M monthly (from firebase reports). Also, it is showing a user retention rate of 72% for day 1 retention. screen_view and user_engagment events show 4.4M and 3.9M count in the last 28 days. the other contradictory metrics are like session_start, which shows only 476K event counts per 28 days. I mean if only a 476k app start events happened, where do the 3.5 monthly users come from?!! Also for first_open event, it is showing a 45k event count per the last 28 days. Engages sessions per user is at 0.08!! which is illogical (should be larger than 1). Google Play reports show no increase in downloads and is about 1k per day. But because of the app's main functionality, I am understanding that many (or maybe most) users are downloading the app outside of Google Play. Also to help you investigate, many users are using the app to reset the google advertising ID. could be that firebase is counting users using the advertising ID by default?! What I want to know is if those users are real or how could I be sure. I have Admob implemented in the app. The number of requests is also higher similar to the number of active users.